An exemplary embodiment of the present invention relates to a circuit arrangement for turning on and turning off a semiconductor component that can be controlled via a gate terminal, said circuit arrangement being suitable for use in the semiconductor device.
It is a known procedure to employ high-power switches in the form of GTOs (gate turn-off thyristors) or GCTs (gate commutated thyristors), for example, in inverters. These semiconductor components are turned on by a gate current pulse. In order to turn off the components, in the case of the GTO, part of the anode current and, in the case of the GCT, even all of the anode current, is fed out of the semiconductor via the gate. In order to ensure that the semiconductor component is turned off homogenously, the turn-off procedure has to be carried out as quickly as possible, that is to say, with a high change rate dIG/dt of the gate current IG. This prevents current filaments that have a very high current density and that could damage the semiconductor from forming in the areas of the semiconductor that are not yet turned off.
FIG. 1 shows a schematic depiction of the circuit diagram of a driver circuit for such a semiconductor component S1. The circuit comprises a turn-on circuit for turning on the component in which the gate-cathode channel (between the gate terminal G and the cathode K), a voltage source U1 and a suitably selected resistor R1 are connected in series. The gate current pulse to turn on the semiconductor component S1 is generated in this electric circuit by means of the voltage source U1. Moreover, the driver circuit comprises an electric turn-off circuit in which a switch S2 as well as a voltage source C1 are connected in series to the gate-cathode channel of the semiconductor component S1. As a rule, the switch S2 is configured as a MOSFET and can be triggered, for example, by the current source U1. As a rule, the voltage source C1 is configured as a capacitor that is charged by means of an energy source U2. The capacitor voltage ensures a rapid increase in the gate current during the turn-off procedure. The capacitor voltage, however, is limited by the blocking ability of the gate-cathode channel. This is why great importance is ascribed to the leakage inductance of the turn-off circuit.
European patent application EP 0 328 778 A1 describes a high-power switch that can be turned off via a gate, whereby the driver unit is divided into a plurality of sub-units that are connected in parallel and integrated into the housing of the high-power switch. This eliminates the need for long feed lines between the gate and the driver circuit, as a result of which the leakage inductance of the electric turn-off circuit is reduced.